ok I don't know what hardly any of that is,
It's pretty straightforward, I'll lend you a hand.
DOOM.wad, DOOM2.wad, PLUTONIA.wad, and TNT.wad are the "iwad" files, these contain all the levels, all the graphics, all the sound effects, all the music, etc. Basically, all of the actual content of the games.
When you pirate Doom, or you pay for it like a sucker, you'll get these files, and then you can use those with whatever setup.
but the steam versions are retard friendly correct?
Yes, they're also properly authentic and accurate in all the ways that matter.
On the console end, the new ports are actually the most authentic console ports of Doom ever, unlike many of the old console ports which varied a LOT, this really is like playing the original PC Doom, just with a controller.
Anyway, if you ever wanted to try out custom content, the official ports accommodate that somewhat (even on console), but not a lot.
For that, I'd suggest a
sourceport like
Woof or
Nugget, they'll play anything made for the 'vanilla' game, and anything that's Boom or MBF21 format, ergo 90% of all the stuff ever made.
Woof and Nugget also have some nice and comfortable optional features you may or may not like, such as the Brightmaps feature, which makes parts of some textures and sprites glow in the dark. It's not in the original game, but it fits Doom's aesthetic like a glove, I think it looks great.
For handling "pwads" and playing them, get a launcher program like ZDoom Launcher, or Doom Launcher.
You open the launcher and add the "iwad" files to it (DOOM.wad, DOOM2.wad, etc, etc), and then you'd point the launcher to which program you're using, be it the Steam version of Doom, or a sourceport like Woof or Nugget.
Next, you'd add the "pwad" with the custom levels you want to play. Let's say you wanted to play Sigil, the set of levels John Romero released a few years back, you'd add SIGIL_v1_21.wad to your launcher. Selecting that one, you'd get a prompt where you're asked to select an iwad, since Sigil is made for the first Doom, you'd select DOOM.wad, and then you'd select the program to play with.
Launchers will let you load up multiple .wad files in one go, so if you also had SIGIL_SHREDS.wad, which contains the .mp3 heavy metal soundtrack by Buckethead, you could add that to your "load order" and it would be loaded into the port together with Sigil (that is, if your port supports playing .mp3 music, not sure if the Steam version does that).
For advanced sourceports like GzDoom, you can use this to play a custom mapset together with a gameplay mod.
Sigil (and also Thy Flesh Consumed) are a lot higher in difficulty than the first game, so I would suggest either playing those on a lower difficulty, or saving them for after having done Doom 2.
I think so. Not sure if they come with mouse support out of the box.
They do. The new ports also let you use the mouse without the back and forth movement which was tied to it in the original .exe, because everyone in the world agreed that it's better that way.